I’m thinking along the same lines as @cardamom. Having correction carbs at 120 may be too late - it leaves you with little room and time available for any further corrections one way or another. As rudimentary as the pump calculations may be, your pump keeps track of IOB. At the time when bg starts dropping convincingly, take a look at IOB as reported by the pump, subtract roughly what would be needed for the “normal” correction from that bg (not that crazy factor you see at times, because whatever was pushing bg up should be over at that point), and take some not-too-fast-not-too-slow correction (chocolate comes to mind) for the remaining IOB. As @cardamom mentioned, even if you over-correct, the worst that can happen is soft landing at somewhat elevated bg, which should then be easier to deal with a follow-up correction.
About the spike itself: is there any way to tell it’s coming? How about a stronger early bolus correction (as opposed to stacking after the fact)? (of course, be ready to correct if the spike was misidentified)